4 2 D4 Opt. FG G2 BOOST GND TG 5 3 INP TS 4 1 Comp 3 2 FB=1.23V R42 0 2.5Vr R22 13.3K R32 294K R29 22.1K 16 Vin 15 Rosc Out 14 4 Sync PGND 13 5 SS/MaxDC Delay 12 6 Vr=2.5V OC 11 7 SD/Vsec Isense 10 8 GND Blank 9 3 R3 47 D10 Opt. 1 C9 100pF D6 B0540W C4 0.1uF 2 CS D7 B0540W C8 100pF Q9 BCX55 2 1 1 R10 1K D8 B0540W T2 PE-68386 Pulse Eng. C7 220pF CU1 1uF 16V 2 Gnd TP2 CO5: See Quick Start Guide R8 2.2 RCS1 0.020 1206 2 Sout 1 6 2 5 3 4 C6 0.22uF 50V Vu1 R23 910 R24 39K CG R12 0 2 C 1 Q14B 5 Sync Sw1 Vfb R18 10K R21 10K U6 PS2801-1 4 1 3 2 R27 270 Vaux C14 1uF 10V Vaux Sync R16 10K R26 100 C23 0.1uF C13 0.47uF 10V Q14A PBSS4140DPN 2 D9 PDZ7.5B C5 0.22uF 50V ( Install 300 ohm In Place Of CO5 ) Vaux R17 560 R20 C11 64.9K 0.01uF U5 LTC3900CS8 1 CS+ SYNC 8 2 CS- TIMER 7 3 CG GND 6 4 VCC FG 5 Vaux R19 38.3K 1% 2 C12 470pF R25 0 Q13A PBSS4140DPN FG Q13B 5 B 2 B R28 442K R33 158K R30 1.2K D11 BAS516 C15 2200pF 250V R31 10 U4 LT4430ES6 1 1 +Vb C16 0.22uF 10V G2 C19 1uF VCC 2 GND 3 OC OPTO 6 COMP 5 FB 4 C17 0.015uF C18 10pF R34 1.96K 3 G1 Q2 PHM21NQ15T RCS2 0.020 1206 A 2 Blank 3 Rblank 4 SGND 5 IN R37 1 C20 Opt. DrVcc 9 Vin 8 FB 7 EN/Shdn 6 R39 Opt. Vu2 R38 18.2K 1% LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY Customer Notice R40 57.6K 4 +Vo1 C24 33pF 2.5Vr R41 332K Linear Technology Has Made A Best Effort To Design A Circuit That Meets Customer-Supplied Specifications; However, It Remains The Customer's Responsibility To Verify Proper And Reliable Operation In The Actual Application. Component Substitution And Printed Circuit Board Layout May Significantly Affect Circuit Performance Or Reliability. Contact Linear Technology Applications Engineering For Assistance. This Circuit Is Proprietary To Linear Technology And Supplied For Use With Linear Technology Parts. C22 2.2uF 10V 5 Q15 Opt. 1 10 OUT GND CS PGND 11 G2 1 R36 1 R35 82.5K 2 U3 LTC4441MS10 Sw0 A Quick Start Guide J2 Q1 PHM21NQ15T R9 47 D To Enable See 3 Vu1 G1 1 2 1 C10 0.1uF R7 Opt. Vu1 U1 LT1952EGN-1 + CO1 CO2 CO5 (Opt.) 4 R6 Opt. 6 2 D1 BAS516 Q7 Q6 HAT2165 Q13,Q14 Are Optional CSYS 470uF 6.3V APXE 3 VCC CG CO3 CO4 100uF 6.3V TDK C2 1500pF 200V C21 220pF Vfb R15 115K Q4 Q5 HAT2165 2 1 Q8 (Opt.) 6 U2 LTC4440ES6-5 A R14 33K Q3 (Opt.) Sw0 Vu2 R5 10 C3 1uF 16V R13 22K 9 1 Vu1 Q12 BC857BF 6 2 TP4 C 8 +Vin 2 -Vin 1 TP1 J1 D3 BAS516 C1 Opt. 2 D5 PDZ9.1B 2 +Vout +Vo1 6 1 Sw1 1 R4 Opt. +3.3V at 40A L1 .65uH PA1382.650 5 2 4 1 4 1 T1 PA0369.003 4 R11 82K Q11 Opt. D2 BAS516 1 3 Q10 PZTA42 Isolation Boundary 2 1 D 1 1 CIN1 CIN2 CIN3 2.2uF 100V TDK 3 1 TP3 CIN4 (Opt.) L2 1.5mH DO1607B-155ML-C Vu1 4 2 2 +Vin R2 0 +Vb 2 1 R1 2.2 3 +Vin 36V-72V 3 1 5 3 2 LINEAR TECHNOLOGY CORPORATION 1630 McCARTHY BLVD. MILPITAS, CA. 95035 408-432-1900 408-434-0507 FAX Title 48Vin to 3.3Vout @ 40A Isolated DC/DC Converter LT1952EGN-1, LTC3900CS8, LT4430ES6 Size Document Number Date: Monday, October 03, 2005 Rev Demo Circuit 830A Sheet 1 1 of 1 A